The Sūtra Spoken by the Buddha on the Precepts of the Five Precepts for Upāsakas (Regarding the Precept against Major False Speech)

Original text:佛告诸比丘。吾以种种呵妄语。赞叹不妄语者。乃至戏笑尚不应妄语。何况故妄语。是中犯者。若优婆塞。不知不见。过人圣法。自言我是罗汉。向罗汉者。犯不可悔。若言我是阿那含。斯陀含。若须陀洹。乃至向须陀洹。若得初禅。第二禅第三禅第四禅。若得慈悲喜舍。无量心。若得无色定。虚空定识处定。无所有处定。非想非非想处定。若得不净观。阿那般那念。诸天来到我所。诸龙夜叉。薜荔毗舍阇。鸠槃荼罗刹。来到我所。彼问我我答彼。我问彼彼答我。皆犯不可悔。 

Explanation: The Buddha said to the bhikkhus: I have rebuked false speech in various ways and praised those who do not speak falsely. Practitioners should not speak falsely even in jest, let alone speak falsely deliberately—still less should they violate this precept. If there truly are those who violate the precept against false speech, if a lay disciple (upāsaka/upāsikā) who has received the five precepts does not know and has not realized any noble dharma surpassing ordinary people, yet tells others, "I am an arhat," "I am one bound for arhatship," "I am an anāgāmin," "I am a sakṛdāgāmin," "I am a srotāpanna," "I am one bound for stream-entry," "I have attained the first dhyāna," "I have attained the second dhyāna," "I have attained the third dhyāna," "I have attained the fourth dhyāna," "I have attained the four immeasurable minds of loving-kindness, compassion, joy, and equanimity;

I have attained the formless realm concentrations of the base of infinite space, the base of infinite consciousness, the base of nothingness, and the base of neither perception nor non-perception; I have attained the contemplation of impurity; I have accomplished the mindfulness of ānāpāna; heavenly beings have come to my side; dragons, yakṣas, gandharvas, piśācas, kumbhāṇḍas, and rākṣasas have come to my side and conversed with me—they ask and I answer, I ask and they answer"—such claims constitute a violation of the precept against false speech, and once violated, it cannot be repented; even if one repents, the karmic offense of false speech cannot be eradicated; there is still guilt, and at the end of life one will fall into the three evil destinies to undergo the retribution of false speech. 

The above is the Buddha's teaching on the precept against false speech, mainly targeting major false speech—untrue lies about extremely grave matters; minor false speech is not addressed here. Regarding grave matters, namely the realization of supramundane dharma, one absolutely must not lie and deceive others with false speech. The offense of impersonating a noble sage is extremely grave. Even impersonating a king would result in beheading and public display, with one's entire clan implicated—how much graver is the offense of impersonating a noble sage who far surpasses worldly ordinary kings; the offense is even greater, cannot be repented, and one will certainly fall into the evil destinies. Therefore, everyone must be extremely cautious and careful with regard to major supramundane dharma. Without one hundred percent certainty, without conclusive evidence, one must never casually spread the claim that one has attained some supramundane dharma. And no matter who has certified you, if it is untrue, you will certainly undergo severe evil retribution. It is hoped that all students of Buddhism will be ever so careful, and not commit the offense of major false speech; once this human body is lost, it will be extremely difficult to encounter again.

Why do so many people like to proclaim outwardly that they have attained such-and-such dharma or achieved such-and-such fruit? What is the psychology of sentient beings here? When examined deeply, it is nothing more than wanting to prove oneself excellent and superior, surpassing others, that "I am better than others, and others are all inferior to me"; or wanting to gain others' reverence, admiration, and respect, wanting others to submit to me, wanting to stand out above the crowd, and so on—thereby being arrogant, narcissistic, and conceited. All of this is based on having both self and others in one's mind, with the mark of self fully present and the mark of others fully present; one has not eliminated self-view and has not attained any dharma, and is therefore still an ordinary being replete with self-view. Those who wish to attain noble dharma must deeply examine their own minds, dig out the "I" within their hearts, and break it up, eliminate it, and destroy it—do not let that "I" come out again to confuse and disturb oneself, adding afflictions, delusive karma, and suffering to oneself.